78 



over ilie .surface of the g'laiid along' its posterior lateral 

 margins, pro\dding numerous branches, and eventually 

 plung-ing- below the surface into the substance of the 

 gland. Other small branches are given olf, on each side, 

 from the aorta, and pass through the gland to supply the 

 stomach. 



Approaching the pit wherein the ligament rests, the 

 aorta curves to the right of the median line so as to bend 

 round the pit, and on reaching its anterior edge plunges 

 down into the midst of the digestive gland, bending 

 slightly to the right, so as to pass the oesophagus on that 

 side. It gives off two vessels, which arise close together 

 on the left side. Both of these leave the gland and pass 

 into the mantle, one curving back to supply the region of 

 the ligamental pit; whilst the other, the anterior pallial 

 artery (fig. 14, A. p. a.), which is larger, passes forwards 

 to the anterior dorsal corner of the mantle, where it 

 bifurcates to form the circumpallial arteries running 

 round the margin of the mantle lobes. It also gives off 

 smaller vessels before dividing, which supply this area of 

 the mantle on both sides. 



The main branch of the aorta passes, as we have seen, 

 into the midst of the digestive gland (fig. 14), and gives 

 off very close to the two vessels above described a small 

 branch which, passing through the gland, reaches the 

 surface again on the left side and passes into the mantle. 

 This will be easily seen (in injections with lard) on the 

 left side of the gland. 



At about the level of the upper lip, a small vessel is 

 given off, passes to the anterior surface, and breaks 

 up to supply the external labial palps and the upper lip 

 (fig. 17, A. I.). The capillaries, or very small vessels, can 

 be followed out on the palps if the injection is successfully 

 carried out. 



